1. Field of the Invention
The invention concerns a foam dispensing article based on a non-aerosol mechanical pump.
2. The Related Art
Foamed compositions are useful in a variety of consumer products. These include compositions intended to clean hard surfaces in households and treating human skin and hair. Illustrative compositions are shampoos, body and hair mousse, shaving creams and hand cleansers.
Non-aerosol devices can generate foam by mixing a foamable liquid with air. A variety of pump devices have been on the market for several years. U.S. Pat. No. 5,337,929, U.S. Pat. No. 5,220,483 B1 and WO 97/13585 all assigned to Airspray International B.V. describe mechanical pump variants which rely upon a chamber for mixing air with a liquid component to express a mousse. Airspray International has provided these devices for delivery of compositions in many commercial products. Some of these are represented by the skin and hair technology disclosed in U.S. Pat. No. 6,030,931 (Vinski et al.) and U.S. Pat. No. 6,264,964 B1 (Mohammadi).
Related mechanical pumps are reported in U.S. Pat. No. 5,364,031 (Taniguchi et al.) wherein nozzles are reported with velocity decreasing structures to achieve thick homogeneous foams. Other related pump configurations are found in U.S. Pat. No. 3,709,437, U.S. Pat. No. 3,937,364, U.S. Pat. No. 4,022,351 and U.S. Pat. No. 4,184,615 all to Wright.
I have found certain shortcomings in the commercially available mechanical pump devices when they are applied for delivering compositions containing surfactants. Unwittingly consumers operate pumps of the aforementioned type in a manner causing various problems. Slow downward pressure on the actuator head increases chances of a slow return for valve closure of the liquid product containment chamber. A tilt of the package then allows liquid to enter the pump vent hole. Once within the air chamber, some liquid product will be trapped. There are two consequences. Lubrication oil on the piston can be solubilized within the liquid product. This causes the piston to stick. Secondly, liquid product absent aeration can dribble from the mouth of the exit nozzle rather than being expressed as a foam.
Accordingly, it would be desirable to have an improved mechanical foam pump system that avoids the sticking of pistons and expression of non-aerated liquid product.